Focus Movement?

[Nathan King]

I have noticed that when I turn on the enlarger focus the grain, turn it off for a moment, and turn it back on while looking through my grain magnifier the grain is not sharp until the light has been on for a few seconds. Is this normal?

 

[snapguy]

no

Does not sound right. Maybe you have some creep in the darkroom --- whoops, I mean some creep in the enlarger. Is there a focus lock? The focus knob or mechanism should be a bit stiff, so there won't be any creep.

 

[Nathan King]

Does not sound right. Maybe you have some creep in the darkroom --- whoops, I mean some creep in the enlarger. Is there a focus lock? The focus knob or mechanism should be a bit stiff, so there won't be any creep.

I thought about that, but the focus comes right back to where I had it properly adjusted after a few seconds with the light source on. The focus knob is quite stiff, and the elevation knob clamps down tight. The effect is very slight and can only be seen through the magnifier. I only noticed because I began looking through the magnifier before I turned on the enlarger once.

 

[mike c]

Can only think about the negative UN-buckling when the light source is turned off . The light has been on for a little while when I focus the the neg so it is probably all ready buckled by that time. Although now I have a glass carrier so no buckling. One other thing I recall when focusing was flexing of the negative in the carrier, due to the fact the bellows is almost air tight which caused a slight difference of air pressure inside to that of the outside air making the negative flex while focusing.

 

[ic-racer]

This is normal behavior when not using a glass carrier.

 

[Nathan King]

This is normal behavior when not using a glass carrier.

Okay. So, I suppose optimum results using a normal carrier involve turning on the enlarger with a piece of cardboard over the lens, waiting, and quickly moving the cardboard out of the way while starting the timer?

 

[winger]

Okay. So, I suppose optimum results using a normal carrier involve turning on the enlarger with a piece of cardboard over the lens, waiting, and quickly moving the cardboard out of the way while starting the timer?

No, the normal way to use a glass-less carrier is to turn it on to focus and leave it on for a bit before focusing. It's the heat from the lamp that's warming the negative and then the negative pops a bit. If you warm it up, then focus, then get the paper ready quickly so it doesn't pop back while the light is off, you should be able to expose the print with the neg focused. Or buy a glass carrier. If you take a long time between focusing and getting the paper in place, the negative cools back off and pops into its original spot. This is more common with 120 or 4x5 than with 35mm. I've actually never had it happen with 35mm. I would also never do 4x5 without glass.

 

[Jim Jones]

Negatives tended to pop in my Omega B-22 during lengthy darkroom sessions. One way to eliminate this is to leave the enlarger on all the time and control the exposure with the red focusing filter.

 

[Rick Jones]

This was a problem with my D-2 until I installed heat absorbing glass. Eliminated the problem once and for all when I replaced the PH211 with an LED head.

 

[Nathan King]

I will have to get some heat absorbing glass. I have remedied the issue in the interim by loading the paper, turning on the enlarger with a gray card covering the lens, letting it warm for five or so seconds and beginning the exposure. I tried preheating the negative, but the time it takes me to situate the fiber paper (which curls upwards and doesn't want to fit into the slot) and make sure it is perfectly situated for an even border allows the negative to cool enough to become an issue. I have compared prints with a loupe and have found slightly sharper grain allowing the negative to heat prior to exposure.

 

[MartinP]

It sounds like a pretty cheap-and-nasty enlarger if there is no heat-absorbing glass before the neg, or possibly it was removed by someone previously. There are plenty of low-cost, high-quality alternative enlargers available if it is not possible to find BOTH a heat-absorbing filter and a double-glass carrier for the enlarger.

 

[Nathan King]

Perhaps it does have some installed and I do not realize it. It's a very gently used Beseler 67. Not the greatest machine, but it fits in my bathroom.

 

[MartinP]

The filter would look like a very thick (several millimetres) piece of special glass, which is designed to absorb infra-red heat (ie. the radiant heat from the bulb which would otherwise be expected to pass through the optical system of the enlarger) and could well be between the condenser assembly and the negative stage. You could look to see if there is an empty bracket which looks as though it should have something in it, at this area of the enlarger.

A heat-filter is possibly one of those parts which may only be fitted to models above the lowest one (if the manufacturer made a low-price starter model for example), though every enlarger I have ever examined has had one. A glass neg carrier is also pretty important in maintaining the negative in one plane, as is a built-in way to zero the optical system alignment for the condensers, neg carrier and focus stage.

 

[Jim Noel]

Two simplesolutions:
1. Heat absorbing glass
2. Use the red filter under the lens to block the iight while you put the paper in the easel. Note that some papers may be sensitive to this color, particularly if hte filter is old and beginning to fade.

 

[Sirius Glass]

Can only think about the negative UN-buckling when the light source is turned off . The light has been on for a little while when I focus the the neg so it is probably all ready buckled by that time. Although now I have a glass carrier so no buckling. One other thing I recall when focusing was flexing of the negative in the carrier, due to the fact the bellows is almost air tight which caused a slight difference of air pressure inside to that of the outside air making the negative flex while focusing.

This is normal behavior when not using a glass carrier.

What they said.

 

[MattKing]

Here is the heat absorbing glass for your enlarger: http://store.khbphotografix.com/Hea...seler-Printmaker-and-67-series-Enlargers.html

I used a 67C for decades - mine was purchased new in the mid to late 1970s. They are very serviceable enlargers. Mine is in storage now, as I'm using an Omega D6 with an Ilford Multigrade head as my enlarger, but if I had the room my Beseler 67C would be set up with it, albeit with a colour head swapped for the condensor head.

The only major downfall, IMHO, of the 67C is that there are no glass carriers available for it.